This disclosure generally relates to medical monitoring systems and devices, and more specifically to a method and system for ECG monitoring.
Electrocardiograms (ECGs) are graphic depictions of electrical activity in the heart. ECGs are produced by electrocardiographs which are available as stand alone devices, portable devices, and/or as integrated functions in various types of multi-vital sign monitoring devices. Typically, ECGs are used as diagnostic tools in various settings, such as hospitals and doctor's offices. ECGs comprise ECG waveforms for each of various leads, which are calculated based on cardiac signals recorded from electrodes attached to the patient. Various ECG recording methods are widely employed using various electrode configurations. To provide just a few examples, 3-lead ECG employing a three electrode arrangement, 5-lead ECG employing a five electrode arrangement, and a 12-lead ECG employing a ten electrode arrangement are all well known in the relevant field, along with other known electrode arrangements. Color coding standards for particular electrode locations are employed so that the electrodes can be visually differentiated, such as the color coding standard developed by the American Heart Association (AHA) and the color coding standard developed by the International Electrotechnical Commission (IEC).
ECGs are depicted by time (ms) versus voltage (μV) and typically are represented as a waveform. The typical five important aspects, or portions, of an ECG waveform are the P wave, QRS complex (represented as the combination of the Q, R, and S waves respectively), and T wave. The less frequently seen sixth portion is a U wave. The data produced from the graphical depictions are useful in diagnosis of patients to determine what, if any, and the extent to which heart-related problems exist in a patient. For instance, ECGs are used in diagnosing: cardiac arrhythmias (irregular heart rhythms), myocardial infarction (heart attacks), hyper- and hypokalemia (high or low potassium levels, respectively), blockage, ischemia (loss of oxygen due to lack of blood flow possibly from blockage), just to name a few, and may also assist in diagnosis of non-heart related ailments. Accordingly, ECGs are known and proven to be valuable tools in diagnosis heart and even non-heart-related problems with patients.
Particularly, the ECG waveforms are useful in determining whether certain conditions exist or the predisposition of such conditions occurring based on established patterns. Particularly, important information can be derived by measuring the time between certain waveforms; commonly reviewed time intervals are those between the P wave and the beginning of the QRS interval (known as the PR interval) and the time between the QRS complex and the T wave (known as the QT interval). Other relevant data may be derived from the PR segment, the QRS complex, and the ST segment.